MatE210 s05 Niebuhr exam1

MatE210 s05 Niebuhr exam1 - Cal Poly State University, SLO...

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Unformatted text preview: Cal Poly State University, SLO 4/ D. Niebuhr Materials Engineering Dept. s rin 2005 MatE210 p g EXam I Noun - _ .gi'fl Answer all questions. Show an your work. State any assumptions. Priced as marked ( ) Short, painless questions. 1. Composites consist of a m «4?; x phase and a Ye } mCo (a whase,(2) ’ 7/ , . or 1:5 2. Schottky imperfections are found in this type of material: W" ' C WW” (2) / z [ 9 To] - ’- 1‘ P l ~fi5 :‘ a @The preferred slip direction for FCC crystals are: l: l 0 l.) (2) ’7— ' «f z i ” @BThe highest density plane in the FCC lattice is ( ‘0 l ) l l7 (2) ’1 Sq) QC) (“déflj Q0 3 5. The most efficient way to make hollow tubes is by QX‘l‘m S 5 b n (2) / . . ‘fi 0 O 6. True stress IS mathematlcally defined as: A ‘ms+.n+.mu:(2) / C) . . . . . . / 0 7. Communism 1s best assomated w1th th1s bonding type Niall {g (2) O O N, 0, (l, 0/ \C (a 8. Hydrogen bonding involves these 2 elements (2) 9. The volume of a unit cell of aluminum (r = 0.143 nm) is (4) A A? 3 FC C Longer Questions... Compare the elastic modulus for each material (higher, lower, etc.): 2024-0 Al alloy (6,, = 175 MPa) or 6061—T651 Al alloy (0 = 375 MPa) (8) ; £3 50 if” € 25 Sam, 44mm jith 4 ELOGFTLS" ‘gL‘Ou/fl L2,» Dam Sine: “Pu/e am: / Lu» a”°‘7 CIW+S 3 E )5 L459] { ON bbafl ' \ Cal Poly State University, SLO D. Niebuhr Materials Engineering Dept. Spring 2005 MatE 210 11'. Calculate the planar densit: for the (110) in chromium. (r = 0.125 nm, BCC) (8) . at Jr to )1 V n @‘omw' Annjflg ; all-0mg oh 4/; we I +ef§e deal ED 4“ x T fifetx 0+ 9 lung M °P 4467,15 - L\r Qrfi“ 1306. r?“ léfa (mm 104‘) q R I“ , r O 3 we? 0M» 6? (giant ~ 6 /) A 3 3 MW : 0LW3Ar'0‘mm7‘ 3”? Qi‘l'om 5 wa “j; M9175 : cw; WOW/0M1 ) " '\ la a ' 2' 5 3V '0':I flow} )mi (4% > v 3 12. If it takes 80 hours to completely recrystallize an aluminum sheet at 250° C and 6 hours at 300° C, calculate the activation energy in kilojoules per mole for this process. (Hint: Arrhenius relationship) R = 8.314 J / k mol (8) 250°C. ‘— 32? K 7 360°C = 373 L ($23 by EEM S/&Ws’§ ’ (€33 K>z/‘§x?t€l 3mm») ,Q/g % A; Ava T (O :KeZQ/AT ‘83 , ‘Q/RT24” 6/272 f : T - Q —\ Cal Poly State University, SLO D. Niebuhr Materials Engineering Dept. Spring 2005 MatE 210 13. If you cast copper into a cube and a sphere of the same volume, which one would solidify faster? Why? (6) (“bi W5 0\ ide “MOMM a? Surf-Fa“ area am so more wax-J is m (on‘i'qcl' ppm Arm cooldsaus A M («5+ 5:: 1+ anew 14. Compare forging to casting with respect to cost and mechanical properties. Give an application where each would be the preferred method. (not a 1971 Gremlin license plate frame ©) (10) \ ’- MS’Hflfi '5 Much ckfiagur +l4arx {offiimfi Since jar in «‘5 J°M as" ox. Muck, slow» am.) 5 1) fl , éifla L155 VrOA“C‘(' (“WW )D’K Marat in A_ mag,” (imam/VI" +19% ,Lwygfl QIa-‘Mc‘i's i1an SM‘UW“ 5am; Mack inJQun 9,05%) 3+3 4150 do“: (a Li‘jw 4gmpz/«4u/U which Math? 2+ 4 5°04 Process“ 6r amid-«ls «Hurl- re1uirt work, ’3‘!) 191 4W0» ‘it 4MM, emu» +145“ vz. £00,052 /wl—am @4ng Qarl‘s rev/rue. fife/5"” Lax— as+r¢nj4k ma WarlLabHJ—I’b purposes / [WM/Palerbox CA/fi do Hv‘i’ WA ’i’c: 51 work‘ea and (avg/cw winir-Mqi S'l'r/Myf'k," MJCOM) ale ‘91,“. a) 0K 0‘54"" 6"“‘4M4’ ,_\_ Cal Poly State University, SLO D. Niebuhr Materials Engineering Dept. Spring 2005 MatE 210 15. You are fabricating the frame for use in the upcoming 35th Anniversary Gremlin X Turbo. You are designing solid aluminum tubes (circular) for the unibody. For maximum strength the tubes must be in a strain hardened condition in their final form. From experiments you determine strain hardening (a.k.a. cold working) to 18 - 23% will achieve the desirable strength and ductility. Design a process to form a 10 mm round bar from a 35 mm bar. The maximum strain hardening is 40% before fracture. (20) ,_ :1wa 4M MM EW- QHA each/adv. H— 40 Au, Val/MA Simona / Caifl Loafi‘ 4'0 0‘4 S lKCJ AJMSIIM) CZ:::::13§wm / ‘ L\ Marx MMS‘é‘ arvu«( Lu?- ‘Dvuvt fem: Ll“,sz 2/, 2% (Him/O : 78/6 Cal Poly State University, SLO Materials Engineering Dept. MatE 210 D. Niebuhr Spring 2005 16. Given 2 materia . A .n d commercially pure molybdenun: (20) a. State whic material has a larger hardness value, why? b. Draw the generic engineering stress-strain curve for both materials following a tensile test. Label E, 0'ys , Guts and (If e. Draw the geometry of the tensile bar after failure for each material. (1. Which material has greater toughness, why? éfi 51"ng WDMIA lfidwc Mom dis,“fl+lbfi§ anal ‘ ( VMM 7C ngi's wkéck gawk; 500A bArflvs 4:: 51449? C ’z (“mks as 4L1; fiery“, WWG‘A'S ‘4‘ka WO‘bEflnun/x QWObAblb WOMl/lnl-l- lqaue fl; Mama? «Hugh: “ Cffiélk ‘l‘p Sffkcmk Lag-llu ?mvin) Us, \‘qar’l hardness 4425-1- ‘1 h a ~c (/6 (re/“W (fins 8.; 69; b) an; /t% 6 ‘3‘ 54: 6 .l E E e 2 am: u Luck 84¢ *"Msf‘U’tH 3‘“ lath-J )5 VOL" "‘ + ls Mia's 4”“ "a M 5,?“ use a 3 0‘3 i R 7 C ( limb, \ (It) A > rub AQL /W 9 \\ gmvu 4' *nal‘ sun. I if“ ‘N‘ u. k ’15 . w Skid—x \ l 9% K Extra Credit! )< 4 17. Astitchintime= Cl 543’ch 18. Name the primary cause of the Sioux City, Iowa DC—lO crash La llurfi ’l'o (2‘ ma li‘ M’l’al +9 YSA £4“ 6" N570?“ wWL (rack. S+¢4w+.e.& c ...
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MatE210 s05 Niebuhr exam1 - Cal Poly State University, SLO...

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